ORTHOSTATIC SUPPORT IN PARAPLEGIC AND AMPUTEE PATIENTS: A CONTROLLED TRIAL

ABSTRACT Introduction: Functional incapacity caused by physical alterations leads to significant limitations in daily activities and has a major impact on the return of people with disabilities to the social space and the workplace. This calls for an evaluation of the long-term influence of the use of a device specially developed for orthostatic posture on the physiological, biomechanical and functional parameters of amputees and spinal cord patients. Objective: The objective was evaluate the effect of postural support device use on function, pain, and biomechanical and cardiologic parameters in spinal cord injury and amputees patients compared to a control group. Methods: The orthostatic device was used by the participants for a period of ten consecutive days, for three cycles of 50 minutes each day, and a 15-day follow-up. Participants were positioned and stabilized using adjustable straps on the shoulders, trunk, and hips. The primary outcome was brief pain inventory. Fifteen participants were included the control group, 15 in the amputee group, and 15 in the spinal cord group. Results: Our results demonstrate that the use of the device allows the orthostatic position of amputees and spinal cord patients evaluated for ten days, leading to improved functionality and pain in the spinal cord and amputee groups compared to the control group. In addition, no changes were observed for secondary outcomes, indicating that the use of the device did not cause harm interference to patients. Conclusion: The long-term use of the orthostatic device is beneficial for improving functionality, reduce pain in amputees and spinal cord injury patients. Level of evidence II; Therapeutic Studies - Investigating the results of treatment .


INTRODUCTION
Functional disability caused by physical alterations leads to significant limitations in daily activities and generates a great impact on the return of people with disabilities into the social space and workplace.][3] About 250.000 to 500.00 people worldwide suffer from spinal cord injury, which results in paralysis, sensorimotor deficit, and consequently sedentary behavior, generating direct effects on health, functioning, and functional independence. 2In the United States, about 1.7 million people reported the loss of a limb in 2007, 4 with the number of lower limb amputations increasing annually due to the high incidence of diabetes and cardiovascular disease. 5he impact of lower limb amputation resulting from traumatic illness or injury is great for walking skills and community engagement. 6onsidering that the number of people affected by both conditions is high and predispose to relevant factors such as limited mobility and social reintegration, inclusion strategies should be prioritized to reduce the psychosocial and physical risks associated with the dysfunction. 7hanges in the spinal cord lead to peripheral and central cardiovascular adaptations such as increased peripheral vascular resistance, reduced capillarization, and decreased artery diameters, which cause static hypotension resulting from a decline in blood pressure, limiting the stand position. 8On the other hand, amputees also show changes in heart rate due to loss of aerobic capacity related to reduced walking ability and show changes in muscle strength and balance due to deconditioning and disuse. 9To re-establishment of the locomotion and mobility functions of patients with physical disabilities related to the lower limb, assistive devices have been developed to allow the standing position and gait. 10,11Thus, the function of the orthoses is to generate stability of the affected limb and, in some cases, assist in the gait pattern with the lowest possible energy consumption. 10,11rgonomic position is necessary and has been developed regarding the need for changes in work to accommodate workers' characteristics. 12Considering that when returning to the work and social environment, the individual with disability needs follow to a specific workplace rules, like a specific workload and specific positions adopted in a laboral environment.That is why limitations in the use of positioning orthosis occur since they generate a very large amount of physical energy expenditure and generated limited mobility.In addition, in most cases, prior training is required to restore the patient's aerobic capacity and strength to do the task. 8,9o the best of our knowledge, this is the first study that aims to assess the influence of the use of a device specially developed for the orthostatic posture on the physiological, biomechanical, and functional parameters of spinal cord and amputee patients in long term.The objective was to evaluate the effect of postural support device use on function, pain, and biomechanical and cardiologic parameters in spinal cord injury and amputees patients compared to a control group.

Design
A non-randomized controlled trial.The study was approved by the Local Ethics Committee (CAAE 30603420.3.0000.5040)and prospectively registered at Registro Brasileiro de Ensaios Clínicos (REBEC) (identifier U1111-1257-5736).All participants were informed about the procedures and signed the written consent form.All methodological steps followed the recommendations of Consolidated Stands of Reporting Trials (CONSORT).

Participants
The participants were recruited between October and December 2020 in the Centro de Pesquisa, Desenvolvimento e Inovação Dell -DELL LEAD.The eligibility criteria were: adults, aged between 18-50 years, height 1.55-1.75cm, maximum weight 100 kg, of both sexes, without associated vascular pathologies (clotting disorders, decompensated diabetes, etc.), with stabilized blood pressure.The control group was composed by healthy people and without motor changes in the lower limbs.In the amputee group was selected people with unilateral lower-limb amputee.The paraplegic group was selected people with diagnostic of a total or partial paraplegic, with a maximum of 10 years of the lesion and without musculoskeletal deformities in lower limbs.The exclusion criteria were: individuals with height and weight outside of the defined, established limits, unstable blood pressure, and severe vascular alterations.Furthermore, they exclude people with cognitive or psychological dysfunction that influence the performance of the tests, like panic syndrome, severe anxiety, or depression.

Intervention
The proposed intervention consisted of using the orthostatic device by the participants for a period of ten consecutive days, used for three cycles of 50 minutes each day, with a 10-minute rest between each cycle and a 15-day follow-up after the end of the experiment.Initially, demographic data were collected and applied to the questionnaires: Brief pain Inventory (BPI), 13 Functional Independence Measure (FIM), 14,15 and sleep quality by Epiworth Sleepiness Scale. 16Then, measurements of vital signs [blood pressure (BP), oxygen saturation (SatO2), and heart rate (HR)] were performed.On a stretcher, the participants were positioned to collect measures of joint range of motion 17 and muscle strength using a handheld dynamometer. 18articipants were positioned in the orthostatic device and stabilized using adjustable straps on the shoulders, trunk, and hips.In addition, a wider velcro band was added in the region of the legs (above the knee) and the region of the tibialis anterior.These bands allowed greater stability of the lower limb in the standing posture, especially for the paraplegic group, due to limitations in motor control.Once positioned, the device was elevated, allowing the participant to remain in the standing position.At the base of the equipment, a mechanism was installed that allowed movement in ankle dorsiflexion to generate mobility in the joint during the orthostatic position.After the volunteers were placed in orthostatism, evaluations of the autonomic nervous system (heart rate variability), body thermography of the trunk, hip, thigh, leg, and feet regions, and plantar pressure by baropodometry were performed.During the proposed period of daily intervention, consisting of three cycles of 50 minutes of standing position, the variables heart rate, oxygen saturation, and blood pressure were measured every 25 minutes to monitor the stability of vital signs.After completing the three cycles of 50 minutes with a 10-minute rest (totaling 3 hours of equipment use), the heart rate variability, body thermography of the trunk, hip, thigh, knee, leg, and feet regions, and plantar pressure were measured again.The volunteers were again positioned on the stretcher, and measurements of range of motion and muscle strength were taken.The study variables were collected at baseline, on the fifth day, at the end of the experiment (tenth day), and at follow-up.

Outcome measures
Trained therapists collected all outcome measurements.The measures were obtained before the intervention (baseline), five days, ten days (end of intervention), and 15 days after the end of intervention (follow up).Functionality was considered the primary outcome.Secondary outcomes were: sleepiness level, pain, plantar pressure, muscle strength, ROM, oxygen saturation, heart rate variability, and thermography.Function, Pain, and level of sleepiness was measured with Functional Independence Measure (FIM) 4, 15  and Brief Pain Inventory (BPI) was used for pain assessment.13  The sleepiness assessment was performed using the Epworth Sleepiness Scale 16  The analysis of mean plantar pressure and stabilometry was performed by a baropodometer (T-Plateda Medicapteurs®, France).19  A FLIR C2 6.4 camera was used to collect thermographic data.Averages of the trunk, hip, thigh, knee, leg, and feet regions were performed.Data were analyzed and edited by FLIR Tools+.The images were captured at a fixed distance of one meter away from the participant, and the room temperature was regulated at 25 degrees.20  Heart rate variability: For data collection, EmWave® software (Quantum Intech, Inc. Boulder Creek, CA, USA) 21  was used.Muscle strength and ROM: The assessment of muscle strength was performed using a manual dynamometer (SP Tech, Medeor MedTech, Santa Catarina, Brazil), with a maximum capacity of 90.72 kgf (200 lbf) and reliable for use in this population.22  Three isometric contractions lasting 15 seconds were performed for trunk extension, knee flexion and extension, internal and external rotation of the hip and and plantar flexion and dorsiflexion of the ankle (Supplemental Material).

Statistical analysis
Statistical analysis followed the intention-to-treat concept and was carried out by a researcher not involved in the evaluation and treatment protocols.A significance level of 0.05 was set.The linear mixed-effect model was applied to the primary and secondary variables."Time" and "group" were considered fixed effects, whereas the participants were considered the random effect.The time by group interaction was included in the analysis to assess the differential effect between the groups at each follow-up.The dependent variable baseline value was included as a covariate to correct possible differences.Statistical analyses were performed using the SPSS.

RESULTS
Forty five participants were included: 15 in the control group, 15 in the amputee group, and 15 in the paraplegic group.The participants' baseline characteristics are presented in Table 1.One individual in the amputee group dropped out for personal reasons and one in the paraplegic group dropped out for blood pressure decompensation.(Figure 1) Differences between groups were shown for the total score and in motor subescale in the functional independence measure of the paraplegic group when compared to the control group at the end of the experiment (p<0.05).An increase in the FIM was also observed for the cognition subscale, indicating an improvement in the values compared to the control group in the follow-up period (p<0.05)(Table 2).For the measure of pain assessed by the BPI, the paraplegic group had evidence of differences with reduced values for the severity subscale at the end of the experiment and for the interference subscale on day five, ten, and follow up assessments (after baseline) when compared to the control group (p<0.05(Table 3).There were no differences within and between groups over time in relation to excessive sleepiness (Supplemental Material).The assessment of plantar pressure showed evidence of differences between the amputee group compared to the control group (p<0.05).The paraplegic group, on the other hand, had lower foot area values in the assessment after five days of device use and lower lateral velocity values when compared to the control group.(Table 4) For the thermography variable, evidence of difference was observed between the control group and the amputee group for the temperature of the hip region, with an increase of 2 degrees at follow-up (p<0.05).The paraplegic group, showed a decrease of 1.87 degrees compared to the control group in the follow-up period and an intra-group reduction (p=0.02) when compared over the evaluation time (Table 5).The analysis of blood oxygen saturation remained within the limit accepted as adequate for patients.(SupplementalMaterial).The heart rate variability data do not show evidence of difference within and between groups over the period evaluated.The stress index variable presented values between 7.9 (3.6) to 10.3 (4.7) in the control group, 7.5 (2.4) to 10 (6.8) in the amputee group, and 5.5 (2.6) to 6.7 (3.8) in the paraplegic group.The sympathetic nervous system showed values between 1.2 (1.1) to 1.9 (1) in the control group, 0.8 (1) to 1.8 (2.9) in the amputee group, and from 0.6 (0.8) to 0.7 (1.1) in the paraplegic group.For the evaluation of the parasympathetic nervous system, values between -0.6 (1.3) to 0.16 (1.5) were observed for the control group, from 0.55 (2.3) to 0.36 (2) for the amputees' group and 1.3 (2.1) to 2 ( 2.7) for the paraplegic group (Supplemental Material).The intra-group evaluation also did not show evidence of difference in muscle strength (Table 5) and range of motion values (Supplemental Material).Differences in knee flexion strength were observed the control group compared with amputees at follow-up (p<0.05) and in the control group compared with the paraplegic group at final and follow-up evaluation (p<0.05).(Table 6)

DISCUSSION
The use of the device allows the orthostatic position of amputees and SCI patients evaluated for ten days, leading to improved functionality and pain in the spinal cord and amputee groups compared to the control group.In addition, no changes were observed for secondary outcomes, indicating that the use of the equipment did not cause harm or negative interference to the patients.In this study, patients with spinal cord injury showed a reduction in the interference values of pain in daily activities with clinically relevant changes 23 on the fifth and tenth days of using the orthostatic device.Considering that the device allowed the individual to stand in an orthostatic posture, the change may have influenced the individual's perception of pain interference in activities.In addition, patients who presented pain in the spinal cord injury group had a clinically important improvement compared to the other groups, suggesting that changing posture and remaining in orthostatism had a great impact for this population.
The SCI group had lower values of hip range of motion after using the device.This finding is expected since amputees tend to have greater mobility, perform posture transfers more easily and need more of the hip joint for dislocations. 24At the same time, patients with spinal cord injury spend most of the time sitting or lying down with limited change in posture. 25he circulatory support system allowed the patients' ankles to be mobilized during the stay in orthostatism, reducing the chances of edema appearing due to the position for a prolonged period and consequently helped in the local circulation avoiding overload in the foot region, which can be confirmed by stability in the measurement of foot area and plantar pressure over time.Trunk and hip stabilization bands helped in weight distribution without generating local temperature increase and discomfort, as observed by thermography and reported by patients.Data on cardiovascular parameters demonstrated stability over time when comparing the control, amputees, and SCI groups.The stability of these parameters is seen as a positive and beneficial factor since patients with spinal cord injury present cardiovascular and autonomic nervous system changes when positioned in orthostatism. 26The results of this clinical trial corroborate with previous study carried out by the research group, which analyzed the immediate effect of the use of orthostatic device and observed stability in the parameters analyzed for spinal cord injury. 27

Study limitations
This study has some limitations, such as the sample size.This population has limitations in locomotion and possibly associated comorbidities that would influence the availability

Figure 1 .
Figure 1.Flow chart of participant inclusion criteria.